Wearing a breathable t-shirt is the best way to stay dry and warm, especially when you take a short break during your hike. The first layer of clothing is very important! A breathable first layer allows the skin to remain dry, even when you perspire. Breathable fabric is therefore preferable to a classic 100% cotton t-shirt, which stores moisture.
Tip for summer hiking: If you choose a t-shirt that covers the neck and shoulders, you won't have to worry about putting as much sunscreen on these areas.